Fluid pressure reducing valve



D. l.. HAY i 7,739

FLUID PRESSURE REDUCING VALVE Filed July 8. 1958 3 Sheets-Sheet l I Pfg. Z

INVENTOR DONALD l.. HA Kob-054550 BYMAT/LDA/HAxEXECUTR/x ATTORNEY Jan. 23, 1940.

D. L. HAY

FLUID PRESSURE REDUCING VALVE Filed July 8, 1938 3 Sheets-Sheet 2 mK M kwy m .WN

INVENTOR DONALDLHAKDECEMSED BYMA77LDAKHAKEXECUTR/X /f/ ATTORNEY Jan. 23, 1940., Q HAY FLUID PRESSURE REDUCING VALVE Filed July 8, 1958 3 Sheets-Sheet 5 QQ vg n .Sm

Patented Jan. 23, 1940 UNITED STATES` yalarmas FLUID PRESSURE REDUCING VALVE Donald L. Hay, deceased, late of Washington,

D. C., by Matilda K. Hay, executrix, Washingtn, D. C.

Application July 8, 1938, Serial No. 218,121

11 Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) This invention relates to fiuid pressure reducing valves and it has a particular relation to pressure reducing valves of the spring loaded type.

One of the objects of the present invention is the provision of a pressure reducing valve of thecharacter described, which will respond quickly and accurately to small variations in pressure, which reduces to a minimum the tendency to 110 chatter and vibrate and which will not freeze during a heavy air delivery.

Another object of the invention is the provision of a valve of the type indicated embodying a plurality of relatively small and light valve units l; which are operable in sequence with fluctuations in pressure, thus dispensing with the single large valve member usually employed and the tendency for the same to leak and become sluggish. With these and other objects in view, as well 2U as other advantages that may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as defined in the appended claims.

in order to make the invention more clearly 30 understood, there are shown in the accompanying drawings, means for carrying the invention into practical use, without limiting the improvements in their useful application to the particular construction, which, for the purpose of eX- planation, have been made the subject of illustration.

In the accompanying drawings:

Fig. l is a vertical sectional view through one form of fluid pressure reducing valve embodying o the invention; y

Fig. 2 is an enlarged vertical sectional view through one of the valve units shown in Fig. 1;

Fig. 3 is a view partly in side elevation and partly in vertical section of another form of valve construction in accordance with the invention;

Fig. 4 is an enlarged fragmentary vertical sectional view through one of the individualvalve units shown in Fig. 3;

53() Fig. 5 isa vertical sectional view through still another form of valve embodying the invention; Fig. 6 is a plan view with parts broken away of the valve structure shown in Fig. 5 and illustrating the individual valve units thereof both 55 in elevation and in longitudinal section;

Fig. '7 is an enlarged vertical sectional view hrough the pilot valve elements shown in Fig.

; and

Fig. 8 is an enlarged longitudinal sectional View through one of the valve units.

Referring to the drawings, and particularly to Figs. 1 and 2 thereof, a iiuid pressure reducing valve constructed in accordance with the invention is shown as comprising a Valve body I0 formed with a high pressure chamber Il com- 1.@ municating with a high pressureopening i2 and at times with a low pressure opening I3 also formed in the body lil. The valve structure also includes a pressure control chamber I4 comprising a cylindrical wall l5, a top plate I6 and a 15y base plate l'l, the latter being clamped in sealing engagement upon a circumferential seat I8, formed on the body l0, by means of a plurality of cap screws i9 which pass through a circumferential flange 2l] on the body I and are screw threaded into the base plate l1. The base plate Il' is formed with an inner circumferential flange 2l dening a low pressure chamber 22 whichis at all times in fluid communication with the low pressure opening i3 through a passageway 23 in 25 the base plate il yand piping 23.

Arranged in a circle within the low pressure chamber 22 -is a plurality of individual valve units, preferably eight in number, each comprising a cylinder ,2i Wihch is threaded into the valve body l0 and which is provided with a plurality of ports 25 for at times establishing communication between the low pressure chamber 22 and the high pressure chamber Il. Mounted for vertical movement in the lower portion of 35 the cylinder 24 is a piston '26 (Fig. 2) provided with a tubular valve stem 2l which extends downwardly throu'gh'a head 28'screw threaded into the lower endof the cylinder. The stems 2l of each of the pistons cooperates with a'valve seat 29 formed on the upper end of a tubular member 30 which is mounted in the body and which at times establishes communication between the high pressure chamber ll and the low pressure outlet I3. Communication is also established between the high pressure chamber 'Il and the cylinder 2li 'above the piston 26 through ports 3| formed in the valve stem 2l and a restricted 'orifice 32 provided in the piston 26. Screwv threadedk into the intermediate portion of the 50 cylinder 24 is a nipple 33 within which a pilot piston valve 34 is mounted for cooperation with a valve seat 35 located at the top of nipple V33. The pilot valve34 is opened when the pressure within the low pressure chamber 22 and in the 55 outlet I3 decreases to a predetermined value, as will later be described, so as to establish communication between the space above the piston 26 and the low pressure chamber 22 through the ports 25, by means of a plunger 36 mounted in the upper portion of the cylinder 24. This plunger is provided with a. stem 37 at its lower end for engagement with the pilot valve 34 and is biased upwardly by means of a coil spring 38.

Also, located Within the low pressure chamber 22 is a circular plate 39 which is xed to the upper end of a stem 46 mounted for vertical movement in a post 4| threaded into the valve body I6 and is urged upwardly by a coil spring 42 encircling the stem and post. The plate 3B is prevented from rotating about its vertical axis by a plurality of guide pins 43 fixed in the body l between the valve units and passing through openings in the plate. The plate 39 carries a plurality of screws 44 which are engageable with sockets 45 formed in the upper ends of the plungers 36 and are adjustable in length so that when the plate 39 is depressed the pilot valves 34 will be opened successively.

Located within the pressure control chamber I4 is a metallic bellows 46 the lower end of which is secured to a ring 4l threaded onto the ange 2| and the upper end of which is secured to a ring 43 threaded onto a cup-shaped spring housing 49. This bellows is the subject of a copending application Serial No. 213,727 led June 14, 1938. The housing 49 extends downwardly through the bellows 46 and bears against the plate 39 through the medium oi a centrally located ball bearing 36 and contains a plurality of concentrically arranged compression springs 5| of varying strength. These springs are confined between retainers 52 and 53, the former being seated in the bottom of the housing 49 and the latter engaging against a thrust bearing 54 interposed between the upper retainer 53 and an adjusting screw 55 threaded into the top plate I6 of the pressure control chamber I4. The interior of the bellows 46 communicates with the low pressure chamber 22 through a port 56 in the ange 2| so that the pressure therein will always be the same.

In operation, let it be assumed that it is desired to effect a reduction from 3000 lbs. per sq. inch pressure in the high pressure supply opening l2 and high pressure chamber 11 to 200 lbs. per sq. inch pressure in the low pressure outlet I3. In this event the adjusting screw 55 is tightened so as to compress the bellows 46 through the medium of the compression springs 5| suciently to balance 200 lbs. pressure within the bellows and low pressure chamber 22. That is to say, the uid pressure within the bellows 46 will maintain the same expanded against the action of the springs 5|, thus permitting the spring 42 to hold the plate 39 in its elevated position and the springs 38 to hold the plunger 36 and stern 31 out of contact with the pilot valves 34. The pilot Valves 34 will therefore be held closed by uid under pressure exerted thereagainst and passing from the high pressure chamber |I, through the ports 3|, valve stem 2l, restricted orifice 32 and nipple 33. This will cause pressure to build up in the space within the cylinder 24 above the piston 26 and hold the valve stem 21 in engagement with its seat 29.

Under these conditions, if the pressure Within the low pressure chamber 22 and in the bellows 46 should drop below 200 lbs. per sq. inch, the springs 5| will compress the bellows and move the spring housing 49 downwardly. This movement of the housing will depress the plate 39 and cause one or more of the adjusting screws 44 to, in turn, depress the plungers 36 and stems 3l so as to unseat the pilot valves 34 against the fluid pressure exerted thereagainst. Fluid under pressure is thus permitted to escape from the space above the piston 26, through the nipple 33, around the pilot valve 34, through the valve seat 35 and ports 25 into the low pressure chamber 22, and since the ports 25 are larger than the restricted orifice 32, the pressure above the piston 26 is reduced. This permits the higher pressure, which has built up in the space beneath the piston 26 through leakage past the valve stem 21 while the pilot valve was closed, to elevate the piston 26 and unseat the valve stem 2l. Fluid under high pressure is thus permitted to iiow from the high pressure .chamber to the low pressure outlet I3. As soon, however, as the pressure within the low pressure outlet again builds up to 200 lbs. per sq. inch and this pressure is transmitted to the low pressure chamber 22 through the piping and passageway 23, and thence to the interior of the bellows 46 through the port 56, the bellows is expanded against the action of the springs 5| and elevates the spring housing 49. This permits the spring 42 to elevate the plate 39 and the screws 44 carried thereby so as to allow the springs 38 to raise the plungers 36 and the stems 3l out of contact with the pilot Valves 34. The pressure beneath the pilot va-lves causes them to close, thus causing pressure above the pistons 26 to build up rapidly and force them down and the stems 2l into engagement with their seats 26. The supply of uid under pressure is thus interrupted until the pressure in the outlet again drops below 200 lbs. to the square inch when the described cycle of operations is repeated.

It will be understood that the pilot valves open successively and in accordance with the adjustments of the screws 44. Hence, if the reduction in pressure is only slight it may be that only one of the main valves will be opened. On the other hand if the reduction in pressure in the low pressule outlet is sudden due to a large demand, several or all of these valves will be opened in rapid sequence so as to replenish the supply of fluid under the desired pressure at a faster rate.

In Figs. 3 and 4 there is illustrated another form of the invention in which the valve in its entirety comprises a block 60 machined from a bar of hot rolled Everdur and having a high pressure chamber 6| formed therein which communicates with a source of iiuid at high pressure through a nipple 62. The block 66 is formed with an upper flange 63 to which a pressure control chamber 64 is secured by bolts 65. A low pressure or expansion chamber 66 is secured to the lower surface of the block 66 by means of bolts 6l. The pressure control chamber 64 comprises a side wall 68 and a cover or cap plate 69 through which the bolts 65 extend and which are clamped together thereby. Communication is at all times maintained between the interior of the pressure control chamber 64 and the low pressure or expansion chamber 66 through ports 'lll and 'H formed in the side walls thereof and which are connected by suitable piping, not shown. Communication is at times established between the high pressure chamber 6| and the low pressure or expansion chamber 66 through laterally extending passages 'l2 (Fig. 4), valve seats 'I3 and outlet passages 14, arranged in line CII along each side of vthe chamber 6|, the passages and valve seats on one side of the chamber being offset or staggered with respect to those on the opposite side. There are preferably eight of these passages and valve seats, four on each side of the chamber 6|.

Threaded into the block 60 above each of the valve seats i3 is a plug 15 having a cylindrical bore l in its lower end closed by a cap or head 'l1 and in which a piston 'F8 is mounted for vertical movement. The piston 'I8 is provided with a hollow stem 'i0 which extends downwardly through the cap 'il and is formed with a conical valve 80 at its lower end for cooperation with its valve seat '13. Communication is, at times, established between the upper end of the bore 16 above the piston I8 through a vertical passageway 8|, the upper end of which terminates in a valve seat 82. Communication lis also established between the high pressure lever 85 which is pivotally mounted on the rounded end yof a post 86 carried by the block y60 within the pressure control chamber 04 and which carries a valve member 8l for movevment into and out of seating engagement with 'its associated valve seat 82.

A spring 88 positioned between the outer end of the lever 85 and a bracket 89 mounted on the block 6| (Fig. 3) biases the valve member 8l toward its closed position.

'Ihe levers 85 are depressed from time to time in order to unseat the pilot valves 81 and reduce the pressure holding the main valves 80 closed, by means of a spring bellows 90 located in the pressure control chamber 64. This bellows consists of a plurality of dish shaped discs 9| suitably secured together around their outer edges,

the uppermost disc bearing against the cover plate 59 and the lowermost-engaging an annular ange 92 provided on the lower end of the tubular stud 03. This stud extends upwardly through the cover plate 60 and has a compression nut 04 screw threaded thereon provided with a head 95 which bears against the upper surface of the cover plate. By means of this construction the bellows 00 may be placed under an initial compression of the desired degree. The interior of the bellows 90 is vented to the outer atmosphere through a port 96 in the cover plate. An adjusting stem 91 is screw threaded into the stud 03 and extends upwardly therethrough and through a packing gland 98 threaded onto the upper end of the stud. The upper end of the stem 91 is provided with an operating handle 99 which is enclosed within a removable cap or cover |00 secured to the top plate 69.

The lower end of the stem 0l is provided with a ball bearing |0| for engagement with a.

pair of longitudinally extending hinged spreader bars |02 each of which is provided with a plurality of adjustable screws |03 for engagement with the levers 85 (Fig. 4). The screws |03 are screwed into the spreader bars |02 varying distances so that vthey will engage and depress v.the levers and unseat the valves 8l in a predetermined sequence.

In vthe operation of the valve structure shown ymitted to flow from the high pressure chamber in Figs. 3 and 4, let it be assumed as before, that the pressure of the fluid in the high-pressure chamber 6| is 3000 lbs. to the sq. inch and that the bellows have been initially compressed by the nut 94 between the top plate 69 and the flange 92, so that when the pressure within the pressure control chamber 64, and in the low pressure chamber 66 reaches 200 lbs. per sq. inch, it will be further compressed and elevate the adjusting stem 91. This will permit the spreader bars |02 and levers 85 vto hold the valves 8l closed under the action of the springs 88. Under these conditions, if the demand on the low pressure side of the valve should decrease a predetermined amount according to the adjustment of the stem 0l and screws |03, say 2 lbs. per sq. inch, the said reduction in pressure will immediately result in a corresponding reduction of the pressure in the W pressure chamber 64. This will permit the bellows 90 to expand and cause the stem 91 to swing the spreader bars |02 so as to carry one of the screws that projects downwardly the greatest distance therefrom, into engagement with its associated lever 85, thus depressing the 2,5 same against the action of its spring 88 andunseat the valve 8l' carried thereby. The opening of the valve 8l' will cause a reduction of the pressure in the bore 'i6 above the piston 18, thereby allowing the greater pressure of the fluid leaking past the valve stem 'l0 into the space below the piston 78, to force the latter upwardly and unseat the valve 80.

Fluid under high pressure will thus be per- 0| into the outlet or expansion chamber 06 until the pressure therein, and in the low pressure chamber 00 again, reaches 200 lbs. per sq. inch. When this occurs the bellows 90 will again be compressed so as to allow the valve 0'! to be closed by the spring 88. As soon as the valve 8l is closed the pressure above the piston 7B builds up almost immediately to a higher pressure while the pressure beneath the piston lags at some intermediate pressure, with the result v that the piston 'I8 is forced down closing the` valve 80 and interrupting the flow of fluid at high pressure to the outlet or expansion chamber 66.

As in the valve structure described in Figs. 1 (50 and 2, the several valve units operate in sequence so as to accommodate rapidly, small or heavy demands on the low pressure side of the valve.

In Figs. 5, 6 and 7 there is shown a still fur- 55 ther embodiment of the invention in which the it' valve in its entirety comprises a lower casting H0 provided with a llange Ill to which a corresponding ange H2 of an upper casting H3 is secured by bolts H4. The upper casting is formed with an upper flange l5 to which a top plate H0 is secured by bolts Ill and is provided with an internal annular flange H8 intermediate its ends which forms a cylinder in which a piston H9 is mountedfor vertical reciprocation..l 65 This piston divides the interior of the castings H0 and H3 vinto a lower outlet or expansion chamber |20 having an outlet l2! and an upper pressure control chamber E22, and is formed with a stud |23 which extends upwardly through `70 the top plate H6 and has an adjusting nut |22` and a lock .nut |25 threaded thereon.

Mounted .on.a seat |20 formed on the lower casting ||0 is a main vvalve yblock |21 and is secured in position thereon ibya highv pressiilem.-I

inlet pipe |28 which extends through the seat |26 for threaded engagement with the block |21A and by a nut |29 threaded onto the pipe |23 exterior of the casting H9. The high pressure inlet pipe |23 communicates at its upper end with a high pressure chamber |39 formed in the block |21 and thence through a plurality of valve units, indicated generally at |3| with the low pressure chamber |20.

With reference to Fig. 6, the valve units |3|, preferably eight in number, are arranged radially and each comprises a plug |32 which is threaded into the block |21. A valve seat |33 is clamped in a recess formed in the inner end of the plug |32 by a cylinder |34, one end of which is threaded into said recess and the other end of which is closed by a cylinder head |35. The cylinder head |35 is formed with a cylindrical protuberance |36 which extends into one end of a cylindrical valve member |31 which is slidably mounted in the cylinder |34 for engagement with the valve seat |33. A plurality of ports |38 are provided in the cylinder |34 for, at times, establishing communication through the valve seat |33, between the high pressure chamber and the low pressure chamber |20. A tubular nipple |39 is threaded into the cylinder head and communicates with a passageway |40 in the protuberance |36. The other end of the nipple |39 projects into a bore |4| provided in a centrally disposed boss |42 which is formed on the valve block |21 and which projects downwardly into the high pressure chamber |30. The inner end of the cylinder |34 is clamped in a socket |43 formed in the boss |42, by the screw plug |32 and leakage therebetween is prevented by a conical gasket |49 interposed between the cylinder head |35 and the bottom of the socket. When the pressure of the fluid in the low pressure chamber is within the desired pressurev range, the valve member |31 is held seated by the pressure of fluid leaking past this valve from the high pressure chamber |30 into the space between the cylinder head |35 and the rear end of the valve.

The high pressure back of the valve is vented in succession in order to allow the higher pressure acting on the front of the same in an 0pposite direction to unseat the valves, when the pressure in the low pressure chamber falls below a predetermined value, by means of a pilot valve mechanism indicated generally at |45. With particular reference to Fig. '7, this pilot valve mechanism comprises a valve body |45 which is clamped in a central recess |41 formed in the block |21, by a nipple |48 threaded into said recess. The valve body |46 is formed with a cylinder |49 in which a piston valve member |50 is mounted for vertical sliding movement into and out of engagement with a Valve seat |5|. Communication is, at times, established between the cylinder |49 and the several bores |4| of the individual valve units, through a plurality of passageways |52, having horizontal portions oirset vertically with respect to one another, and opening into the cylinder |49 at different levels so that they will be uncovered one at a time as the valve member |50 moves down.

The piston Valve |50 is connected by a tubular stem |53 with a cylinder |54 which is mounted for sliding movement in a lower spring retainer |55 carried by the valve body |46. The piston valve |50 is urged upwardly into seating engagement with its seat |5| by a coil spring |56 interposed between the lower retainer |55 and a spring retainer |51 threaded onto the upper end of the cylinder |54. Mounted on a stem |58 within the cylinder |54 is a bleed valve member |59 which is urged toward a valve seat |60 threaded into the upper spring retainer |51, by a spring |6| interposed between the bottom of the cylinder |54 and a follower |62 xed to the lower end of the stem |53. The stem |53 extends a short distance above the bleed valve |59 and loosely through the valve seat |60, for a purpose presently to be described.

Located within the pressure control chamber |22 is a metallic bellows |63, similar to those hereinbefore described. This bellows is placed under the desired initial compression by means of the compression unit |24, its interior being vented to the outer atmosphere through a port |64 in the top plate |6. An adjusting screw |65 is threaded into the lower surface of the piston |9 for engagement with the bleed valve stem |53 and the upper spring retainer |60, and may be rotated to adjust the distance it extends below the piston by a rod |66. This rod is xed to. the upper end of the screw |05 and extends upwardly through the stud |23 and a packing gland |31 carried thereby to a point where it is accessible for adjustment. The end of the rod |66 and the nuts |24 and |25 are enclosed within a removable cover |68 secured to the top plate ||6.

In the operation of the Valve structure just described, let it again be assumed that the uid pressure in the inlet pipe |28 and in the high pressure chamber |30 is 3000 lbs. per sq. inch and that the pressure within the low pressure chamber |29 and the pressure control chamber |22 is 200 lbs. per sq. inch, the pressure to which the spring bellows |63 is adjusted. Under these conditions the bellows |93 will be compressed by the piston |59 as well as by fluid under pressure leaking past the piston so as to hold the adjusting screw out of engagement with the bleed valve stem |58 and the upper spring retainer |63. This permits the spring |6| to hold the bleed valve |59 closed so that fluid under high pressure will build up through leakage back of the piston valve |50 and hold this valve also closed. This same pressure will also hold the valve |31 in a closed position, as hereinbefore explained, so as to interrupt communication between the high pressure chamber |30 and. the low pressure chamber |20.

If, now, the demand on the low pressure side of the system should cause the pressure within the low pressure chamber to decrease a predetermined amount, say 2 lbs. per sq. inch, the spring bellows |63 will expand and cause the adjusting screw |65 to depress the stem |58 and open the bleed valve |59. This will permit the fluid under high pressure to escape from the space behind the piston valve |50 through the tubular stem |53 and valve seat |60 into the low pressure chamber |20 at a rate faster than it can leak into this chamber. The volume of fluid thus suddenly released from the chamber is negligible as compared with that on the outlet side of the valve and therefore does not appreciably affect the pressure thereof. The adjusting screw |55 in its descent next engages the spring retainer |51 and forces it, the cylinder |54, and the piston valve |50 connected thereto, downwardly against the action of the spring |56, the pressure behind the valve |59 having been relieved by the opening of the bleed valve |59. Were it not for the bleed valve |59, the bellows |63, which expands at pressures below 200 lbs. per sq. inch, could not overcome the pressure of 3000 lbs. per

sq; inch gradually built up through leakage in the cylinder |49. As the piston valve I5@ moves downwardly it will first uncover the uppermost of the passageways E52, thereby also permitting the escape to the low pressure chamber IM, of the fluid under high pressure which is connned back of the piston valve |37, of the valve unit isi in, communication with this uppermost passageway. This will permit huid under high pressure within the high pressure chamber I3@ to unseat the valve i3? and flow into the low pressure chamber |20 through the ports l38, valve seat |33 and screw plug |32.

As soon as the uid pressure within the low pressure chamber |25! and in the pressure control chamber |22-has again built upto 200 lbs. per sq. inch the bellows |63 will be collapsed sufficiently to raise the adjusting screw H55, thereby permitting the spring l5@ to close the piston valve |50 and the spring Mii to close the bleed valve |59. Fluid under high pressure will now leak past the valves |31 and l5@ and build up back of these valves sufliciently to close the f'ormer and maintain the latter closely seated on its seat l5! This interrupts the flow of fluid under high pressure to the low pressure chamber |20. As in the valve structures previously described, if the demand on the low pressure side of the system is large7 the piston valve ld will be depressed a great amount so as to uncover a suiicient number of the passageways |52 and actuate the associated valves |31 to accommodate such increased demand.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of the invention and that various changes in construction, proportion and arrangement of the parts may be made within the scope of the appended claims without sacricing any of the advantages of the invention.

The invention ldescribed herein may be manufactured and/used by or for the Government of the United States of America f'or governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

l. A fluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units for controlling communication between said chambers, pilot valve means for controlling the operation of said main valve units and means responsive to the pressure of the fluid in said low pressure chamber for actuating-said pilot valve means in sequence.

2. A fluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamberfor controlling communication between said chamber, pilot valve means for controlling successively the operation of said main valve units, and means responsive to the pressure of the iiuid in said low pressure chamber for operating said pilot valve means.

3. A iluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, pilot valve means for controlling successively the operation of said main valve units, and a bellows responsive to the pressure of the fluid in said low pressure chamber for operating said pilot valve means.

ll. A uid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side ci a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, a pilot valve for controlling the operation of each of saidmain valve units, and means responsive to the pressure of the fluid in said low pressure chamber for operating said pilot valves in sequence.

5. A iiuid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a fluid pressure system, a low pressure chamber,

adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controllingl communication between said chambers, a pilot valve for controlling the operation of each of said main valve units, and a spring loaded bellows responsive to the pressure of the iluid in said low pressure chamber for operating said pilot valves in sequence.

6. A fluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, a single pilot valve for controlling successively the operation of said main valve units, and means responsive to the pressure of the fluid in said low pressure chamber for operating said pilot valve means.

7. A fluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure Side of a fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, pilot valve means for controlling successively the operation of said main valve units, bleed valve means for controlling the operation of said pilot valve means, and means responsive to the pressure of the fluid in said low pressure chamber for operating successively said bleed valve means and said pilot Valve means.

8. A fluid pressure reducing valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of av fluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, a single pilot valve for controlling successively the operation of said main valve units, a bleed valve for controlling the operation of said pilot valve, and means responsive to the pressure of the fluid in said low pressure chamber for operating successively said bled valve and said pilot valve.

9. A uid pressure reducing valve comprising a high pressure chamber adapted to be communicablyconnected with the high pressure side of auid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of radially extending main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, a single pilot valve for controlling successively the operation of said main valve units, bleed valve means for controlling the operation of said pilot valve, and means responsive to the pressure of the uid in said low pressure chamber for operating successively said bleed valve and said pilot valve.

10. A iiuid pressure reducing Valve comprising a high pressure chamber adapted to be communicably connected with the high pressure side of a uid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of radially extending main valve units operable by the I pressure of the fluid in said high pressure chamber for controlling communication between said chambers, a single pilot valve for controlling successively the operation of said main valve units, a bleed valve disposed within said pilot valve for controlling the operation of said pilot valve, and means responsive to the pressure of the fluid in said low pressure chamber for operating successively said bleed valve and said pilot valve.

11. A fluid pressure reducing valve comprising a high pressure chamber adapted to communicably connected with the high pressure side of a iluid pressure system, a low pressure chamber adapted to be communicably connected with the low pressure side of said system, a plurality of main valve units operable by the pressure of the fluid in said high pressure chamber for controlling communication between said chambers, pilot valve means for controlling successively the operation of said main valve units, bleed valve means for controlling the operation of said pilot valve means, and bellows means responsive to the pressure of the fluid in said low pressure chamber for operating successively said bleed valve means an said pilot valve means.

MATlLDA K. HAY.

Eecutrz'x of the Estate of Donald L. Hay, De-

ceased. 

